DE112021001919T5 - BLOOD PUMP - Google Patents

Abstract

This invention relates to an intravascular blood pump (1) comprising a pumping device (11) having a pump section (3) and a drive section (4), the pump section (3) comprising a pump housing (2) having a primary blood flow inlet (211) and a primary blood flow outlet (22) hydraulically connected by a primary passage (30), and the drive section (4) comprises a stator (40) and a rotor (41) rotatable about an axis of rotation (10) and so configured that it rotates a primary impeller (31), the primary impeller (31) being configured to promote a primary blood flow from the primary blood flow inlet (211) to the primary blood flow outlet (22) along the primary passage (30), the drive section (49) further comprising an auxiliary blood flow inlet (23) and an auxiliary blood flow outlet (24) hydraulically connected by an auxiliary passage extending through an axial gap (401) between the rotor (41) and the stator (40), and an auxiliary impeller (42) arranged at a drive section end (DSE) of the rotor (41) and rotatable together with the rotor about the axis of rotation (10), the auxiliary impeller (42) having one or more auxiliary impeller blades (421) configured to promote an auxiliary blood flow (ABF) from the auxiliary blood flow inlet (23) to the auxiliary blood flow outlet (24) along the auxiliary passage in a direction towards a pump section end (PSE) of the pumping device (11), and the Rotor (41) is mounted in a blood flushed radial plain rotor bearing (47) having an inner rotor bearing surface (4211) and an outer rotor bearing surface (4311), and the auxiliary impeller (42) forms the inner rotor bearing surface (4211) of the radial plain rotor bearing (47).

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to an intravascular blood pump for supporting or replacing the function of the heart by generating an additional blood flow in a patient's blood vessel.

BACKGROUND OF THE INVENTION

Various types of blood pumps are known, such as axial blood pumps, centrifugal blood pumps, and mixed or diagonal blood pumps, in which blood flow is caused by both axial and radial forces. Intravascular blood pumps are usually introduced percutaneously, e.g. B. through the far oral artery into the left ventricle to bypass the aortic valve, or through the femoral vein into the right ventricle.

A rotating blood pump has an axis of rotation. In this patent application, the terms "radial" and "axial" refer to the axis of rotation and mean "in a radial direction with respect to the axis of rotation" and "along the axis of rotation", respectively. The term "inside" means radially toward the axis of rotation and the term "outside" means radially away from the axis of rotation.

An intravascular blood pump usually includes a pumping device as a main component. The pumping device has a pump section with a primary impeller for pumping the blood from a blood flow inlet to a blood flow outlet and a driving section with a motor for driving the primary impeller. The pump section may include a flexibly bendable cannula between the blood flow inlet and outlet.

The pumping device includes a pump section end arranged on a pump side of the pumping device. The pumping device further includes a drive portion end disposed on a drive side of the pumping device. The blood pump may further comprise a catheter connected to the pumping device to supply the pumping device e.g. B. with energy and / or a rinsing liquid. The catheter may be connected to the pump section end, but most often is connected to the drive section end of the pumping device. It is also conceivable to rotate the impeller in a forward and reverse direction. Then the blood flow inlet and the blood flow outlet of the pump section can switch.

The impeller is usually mounted within the pumping device by means of at least one impeller bearing. There are different types of impeller known such. B. plain bearings, especially hydrodynamic plain bearings, pivot bearings, hydrostatic bearings, ball bearings, etc., and combinations thereof. In particular, contact-type bearings can be realized as “blood-immersed bearings”, where the bearing surfaces are in contact with blood. Operational issues can include friction and heat. In the case of a blood-soaked bearing, another problem can be blood clotting due to heat or insufficient flushing.

An example of a blood-flushed radial plain bearing is in WO 2017/021465 disclosed. 33 of this document discloses an impeller device comprising a generally cylindrical primary impeller. Primary impeller blades of the primary impeller extend in the direction of an axis of rotation of the primary impeller. The tips of the primary impeller blades form an outer rotor bearing surface of a plain bearing. A cylindrical surface of a bolt located in the center of the primary impeller forms the inner rotor bearing surface of the journal bearing. In order to cool a rotor and a stator of a drive unit, an auxiliary impeller which is rotatable with the rotor is provided on a side of the drive unit opposite the primary impeller. The auxiliary impeller pumps blood into an axial gap between the stator and the rotor. At an axial end of the auxiliary impeller, a sliding bearing is arranged between inner ends of the auxiliary impeller and a bearing pin. This construction requires a lot of axial space and thus leads to a voluminous blood pump that can only be advanced into a blood vessel with difficulty.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a compact blood pump with blood flow through the axial gap between the stator and the rotor.

This is achieved according to the present invention by a blood pump having the features of independent claim 1. Preferred embodiments and further developments of the invention are given in the dependent claims.

According to a first aspect of the invention, an intravascular blood pump comprises a pumping device with a pump section and a drive section. The pump section includes a pump housing having a primary blood flow inlet and a primary blood flow outlet hydraulically connected by a primary passage. The drive section includes a stator and a rotor rotatable about an axis of rotation and configured to have a primary impeller in offset rotation. The primary impeller is configured to promote primary blood flow from the primary blood flow inlet to the primary blood flow outlet along the primary passage. The drive section further includes an auxiliary blood flow inlet and an auxiliary blood flow outlet hydraulically connected by an auxiliary passage such that auxiliary blood flow can be promoted from the auxiliary blood flow inlet to the auxiliary blood flow outlet along the auxiliary passage. The auxiliary passage includes an axial gap extending between the rotor and the stator. The axial gap is preferably also a magnetic gap of an electric motor comprising the stator and the rotor. There is also an auxiliary impeller disposed at the drive end of the rotor, rotatable about an axis of rotation together with the primary impeller, and having one or more auxiliary impeller blades configured to promote auxiliary blood flow through the auxiliary passage. The blood pump also includes a blood-flushed radial plain bearing for mounting the rotor. The radial slip rotor bearing includes an inner rotor bearing surface and an outer rotor bearing surface. The auxiliary impeller forms the inner rotor bearing surface of the radial sliding rotor bearing. Thus, the blood-flushed plain bearing of the auxiliary impeller is arranged radially outside of the auxiliary impeller. In this way, an axially compact blood pump can be built.

Preferably, the blood flushed radial slip rotor bearing is located near an outer periphery of the pump housing so that heat conduction can occur from the outer rotor bearing surface through the pump housing to a surrounding general blood flow. This can help build a compact and reliable blood pump in which heat is effectively removed. This can also help ensure cooler blood is delivered to the axial gap.

The auxiliary impeller is preferably a radial or radial-axial conveying impeller. Thus, the auxiliary impeller generates centrifugal forces in the auxiliary blood flow to generate pressure.

The inner rotor bearing surface formed by the auxiliary impeller and the rotor preferably have a common outer diameter. The auxiliary blood flow can then enter the axial gap without appreciable deflection. In view of the fact that an intravascular blood pump must have a small outer diameter because it has to be advanced through blood vessels to the heart, the structural space in the radial direction is optimally utilized by the feature of a common outer diameter of the inner rotor bearing surface and the rotor. That is, the pressure in the blood entering the axial gap is increased by the auxiliary impeller to the limits, which are limited only by the radial space at the drive section end of the blood pump.

Preferably at least two, more preferably at least three, auxiliary impeller blades extend to the outer rotor bearing surface. The respective faces of the auxiliary impeller blades closest to the outer rotor bearing surface together form the inner rotor bearing surface. This is the surface of the auxiliary impeller on which the rotor is mounted relative to the outer rotor bearing surface. Thus, the inner rotor bearing surface is discontinuous and consists of at least two, preferably at least three, separate sections formed by the tips of the impeller blades. In this way, the tips of the auxiliary impeller blades can form part of a radial slip rotor bearing. The outer rotor bearing surface may be a single continuous surface. Alternatively, the outer rotor bearing surface can also have grooves and/or slots.

At least one auxiliary impeller blade preferably protrudes from the auxiliary impeller in the axial direction relative to the axis of rotation. In this way, the blades can form an axial end of the rotating part of the blood pump. This axial end can be open to allow blood to flow into the auxiliary impeller.

Preferably, a radially outer edge of at least one auxiliary impeller blade is chamfered. A corresponding bevel can be arranged between a section of an auxiliary impeller blade that extends in the axial direction and a section of an auxiliary impeller blade that extends in a radial direction with respect to the axis of rotation. In particular, the blood pump can have a tapering section with a larger diameter in the axial direction between the supply catheter and the pump housing. The taper makes it easier to advance the pump through a blood vessel. Preferably, the bevel of the auxiliary impeller is located below the tapered portion. In this way, the bevel allows a more compact blood pump to be built.

At least one auxiliary vane preferably forms an auxiliary pump gap with an inner wall of the pump housing or with a further part arranged therein. The auxiliary pump gap preferably has a radial outer boundary which extends axially and forms part of the radial rotor journal bearing. Preferably, the auxiliary pumping gap further includes a radially extending axial end portion disposed between at least one auxiliary impeller blade and an inner wall of the pump casing, preferably at a chamfered end of a radially extending extending end surface of the blade. The radially extending portion of the pump gap maintains the pressure built up by the auxiliary impeller blades. The formation of this gap in the axial-radial direction, z. B. along a slope, helps to build a compact blood pump. In particular, the pump housing can be tapered at the point of the bevel.

Preferably at least one, most preferably all, of the auxiliary impeller blades are straight in the direction of their radial extent. Preferably, at least one, preferably all, auxiliary impeller blades extend approximately or exactly along a radial direction with respect to the axis of rotation or obliquely to this direction. The pumping effect of auxiliary impeller blades, which extend in the radial direction, is independent of the direction of rotation of the auxiliary impeller. Especially auxiliary impeller blades of the auxiliary impeller tend to cause less blood clotting.

It is preferable that the outer peripheral surface of at least two, preferably at least three, auxiliary impeller blades has a slope that increases in a radial direction with respect to the axis of rotation along a peripheral direction of the auxiliary impeller. In this way, a planar hydrodynamic rotor bearing can be formed by the tip of the blades in combination with a generally annular outer rotor bearing surface. The slope is configured in such a way that a pressure build-up in a bearing gap of the hydrodynamic sliding rotor bearing is achieved in one direction of rotation. The slope may extend over the entire width of the auxiliary impeller blade in its circumferential direction. Alternatively, it is also possible to provide two slopes in opposite directions, starting from opposite ends of a tip of an auxiliary impeller blade along the periphery of the auxiliary impeller, so that a maximum radial lift of the auxiliary impeller blade is achieved in an intermediate portion of a part of the tip of the auxiliary impeller blade. Such an impeller can be operated in two opposite directions of rotation. Equivalent structural details may additionally or alternatively be provided in the outer impeller bearing surface.

Preferably, the above specifications of the outer peripheral surface are applied to an axial or radial-axial end surface of an auxiliary impeller blade. An end surface of the auxiliary impeller blade may extend in a radial direction with respect to the axis of rotation or along a chamfer arranged on an edge of the auxiliary impeller blade. The aforementioned types of hydrodynamic end surfaces of the auxiliary impeller vanes can be realized in bearing surfaces of an inner slip rotor axial bearing or slip rotor axial-radial bearing between the auxiliary impeller and a non-rotating part of the blood pump, such as the pump housing. An outer axial or axial-radial rotor bearing surface of the axial sliding rotor bearing can be arranged on the pump housing, for example. Axial forces of the impeller can be transferred with the axial or axial-radial rotor bearing.

The axial or axial-radial rotor bearing surface is preferably made of a ceramic material. The ceramic material can be provided, for example, as a ceramic coating. Alternatively, the corresponding sections of the impeller and/or the pump housing can also consist entirely of ceramic material.

A radially protruding bead is preferably arranged on the outer and/or on the inner rotor bearing surface, the apex of which extends in the circumferential direction. The ridge may extend on the outer or inner rotor bearing surface. Preferably the radius of the apex is greater than one tenth of the diameter of the auxiliary impeller. Such a protruding bead has the advantage that when the rotating part of the blood pump pivots transversely to the main direction of rotation, no sharp edges at one end of the rotating part touch a surrounding non-rotating part which would otherwise damage the pump surface. Instead, only the protruding bead touches the non-rotating mating surface. Therefore, the risk of damage to the rotor bearing due to a pivoting axis of rotation is reduced.

Preferably, the inner rotor bearing surface is made of a ceramic material. For example, the inner rotor bearing surface can be provided as a ceramic coating. The hardness of a ceramic material improves the wear properties of the inner rotor bearing surface. Preferably, the ceramic material is inert with respect to reactions with blood.

Preferably the auxiliary impeller is an integral piece of ceramic material. It is also possible that the auxiliary impeller consists of a non-ceramic material coated with a ceramic material.

The outer rotor bearing surface is preferably also made of a ceramic material. For example, the outer rotor bearing surface can be provided as a ceramic coating.

Preferably, the pumping device comprises a special component which forms the outer rotor bearing surface of ceramic material, such as. B. a rotor bearing ring. A separate ceramic component ensures good dimensional stability of the outer rotor bearing surface, which is particularly important because of the small inner rotor bearing surface and the increased surface pressure at the tips of the auxiliary impeller blades.

Preferably the ceramic material is silicon carbide. Silicon carbide has the advantage of having high thermal conductivity compared to most other ceramic materials. This allows the heat to be effectively dissipated from a sliding rotor bearing. The heat conduction can B. through the rotor to the impeller or through the pump housing, in particular through the rotor bearing ring.

The axial length of the auxiliary impeller is preferably smaller than a maximum outer diameter of the auxiliary impeller. In this way, the auxiliary impeller does not extend excessively along the axis of rotation, but is a narrow component in the blood pump. The pumping effect is then mainly generated in the radial direction, which is more effective than in the axial direction. This is advantageous for building a compact blood pump.

Preferably, the primary impeller is arranged on a side of the rotor which is opposite to the side of the rotor on which the auxiliary impeller is arranged. This arrangement has the advantage that a bearing at one end of the rotating parts of the blood pump, such as. B. a radial plain bearing on the auxiliary impeller, which supports the rotating parts optimally in terms of rigidity against pivoting of the axis of rotation.

Preferably, the auxiliary blood flow outlet is located outside the primary passage of the primary impeller. This separates the auxiliary blood flow from the primary blood flow. The blood conveyed through the auxiliary passage then only mixes with the blood from the primary passage outside the primary passage. This results in lower hydraulic losses as the blood flows are in opposite directions and makes the auxiliary blood flow independent of the primary blood flow which is dependent on preload and afterload conditions. In other words: by separating the primary blood flow from the auxiliary blood flow, the latter is only dependent on the pump rotation.

Preferably, the auxiliary blood flow outlet is disposed obliquely or perpendicularly to a direction of main blood flow delivered by the pump section. When the main blood flow flows alongside the auxiliary blood flow outlet, blood is drawn from the auxiliary blood flow outlet by the Venturi effect. This supports the auxiliary blood flow.

Preferably, the auxiliary blood flow inlet comprises a plurality of inlet holes. The inlet holes are preferably arranged circumferentially around the axis of rotation. Preferably the inlet holes are arranged in a circle. It is further preferred that a wire duct is arranged in a space between two adjacent inlet holes. The wire duct can be used, for example, to accommodate at least one electrical supply wire for the drive unit. Such an arrangement of inlet holes and wire channels enables a compact construction of the blood pump.

The axial gap between rotor and stator is located downstream of the auxiliary impeller. The auxiliary impeller may be located in a cavity between the auxiliary blood flow inlet and the axial gap. In particular, the auxiliary impeller conveys the blood radially or radially-axially. An auxiliary inlet through hole is located in the wall of the pump housing along the auxiliary blood flow passage downstream of the auxiliary blood flow inlet. From the auxiliary inlet port, the blood can enter the lumen at an internal end of the auxiliary inlet port. The internal end of the auxiliary intake through hole is preferably located more radially inward than the axial gap. Centrifugal forces acting between an inner portion of the auxiliary impeller and an outer portion of the auxiliary impeller generate pressure to force the blood through the axial gap. In particular, a radially outermost portion of the auxiliary blood flow inlet may be located further radially inward than a radially innermost portion of an inlet into the axial gap.

Preferably, the pumping device also includes a tertiary impeller. The tertiary impeller is preferably located downstream of the axial gap. Preferably, the tertiary impeller is configured to draw blood from the axial gap. The tertiary impeller thus increases the flow rate of blood through the auxiliary passage.

The tertiary impeller is preferably rotatable about the axis of rotation. The tertiary impeller can be rotatable together with the rotor.

Preferably, the auxiliary blood flow outlet is located in a radial gap formed between the primary impeller and the stator. It is preferable that the blood can drain from the radial gap over an entire outer peripheral cross section of the radial gap. Such a large outlet area reduces the hydraulic resistance of the auxiliary blood flow passage.

In particular, a rotatable wall of the radial gap is rotatable together with the rotor. In this way, a spiral drag flow of blood is created, which is caused by its rotation within the gap increases blood flow through the auxiliary passage by means of centrifugal forces on the blood in the helical drag flow.

Preferably, a stationary wall of the radial gap is located opposite the rotatable wall of the radial gap. The stationary wall is preferably mechanically connected to the stator.

Preferably, the tertiary impeller is located within the radial gap. Preferably, the tertiary impeller forms part of the rotatable wall of the radial gap. Preferably, the tertiary impeller includes at least one tertiary impeller blade. The tertiary impeller blade is preferably configured to convey blood in a radial direction. The tertiary impeller blade may extend approximately or exactly in a radial direction with respect to the axis of rotation. Then the effect of the tertiary impeller is independent of the direction of rotation of the tertiary impeller.

Preferably, an inflow into the tertiary impeller is located at an outflow end of the axial gap. The tertiary impeller thus advantageously draws in blood directly from the axial gap. A short connection between the axial gap and the radial gap reduces hydraulic resistance along the auxiliary blood flow passage.

character list

• 1 zeigt einen Querschnitt einer ersten Ausführungsform einer Blutpumpe gemäß der Erfindung,
• 2 zeigt einen Teil von 1 mit dem Pumpenabschnitt in einer vergrößerten Ansicht,
• 3 zeigt einen Teil von 1 mit dem Antriebsabschnitt in einer vergrößerten Ansicht,
• 4 zeigt eine perspektivische Ansicht auf das Pumpenabschnittende der ersten Ausführungsform der Blutpumpe,
• 5 zeigt im Wesentlichen die Ansicht von 4, jedoch mit einem transparenten Pumpengehäuse,
• 6 zeigt im Wesentlichen die gleiche Ansicht wie 5, jedoch eine zweite Ausführungsform der Blutpumpe,
• 7 zeigt eine perspektivische Ansicht einer Ausführungsform des Sekundärlaufrads,
• 8 zeigt eine perspektivische Ansicht eines Separatorrings der ersten Ausführungsform der Blutpumpe,
• 9 zeigt eine perspektivische Ansicht eines Separatorrings der zweiten Ausführungsform der Blutpumpe,
• 10 zeigt einen Querschnitt des Antriebsabschnittendes der Blutpumpe in einer perspektivischen Ansicht, in der ein Hilfslaufrad zu sehen ist,
• 11A zeigt eine perspektivische Ansicht des Hilfslaufrads und eines Rotorlagerrings, 11B zeigt eine perspektivische Ansicht eines Rotorlagerrings mit Aussparungen, und
• 12 zeigt eine perspektivische Ansicht eines Tertiärlaufrads der ersten oder zweiten Ausführungsform.

The foregoing summary, as well as the following detailed description of the preferred embodiments, will be better understood when read in conjunction with the accompanying drawings. However, the scope of the disclosure is not limited to the specific embodiments shown in the drawings. In the drawings:

• 1 shows a cross section of a first embodiment of a blood pump according to the invention,
• 2 shows part of 1 with the pump section in an enlarged view,
• 3 shows part of 1 with the drive section in an enlarged view,
• 4 shows a perspective view of the pump section end of the first embodiment of the blood pump,
• 5 basically shows the view from 4 , but with a transparent pump housing,
• 6 shows essentially the same view as 5 , but a second embodiment of the blood pump,
• 7 shows a perspective view of an embodiment of the secondary impeller,
• 8th shows a perspective view of a separator ring of the first embodiment of the blood pump,
• 9 shows a perspective view of a separator ring of the second embodiment of the blood pump,
• 10 Figure 12 shows a cross section of the drive section end of the blood pump in a perspective view showing an auxiliary impeller,
• 11A shows a perspective view of the auxiliary impeller and a rotor bearing ring, 11B shows a perspective view of a rotor bearing ring with recesses, and
• 12 12 shows a perspective view of a tertiary impeller of the first or second embodiment.

DETAILED DESCRIPTION

In 1 1 is a cross-sectional view of a first embodiment of an intravascular blood pump. Rotating parts are not shown in section. The intravascular blood pump 1 comprises a pumping device 11 and a supply line in the form of a catheter 5 attached thereto.

The pumping device 11 comprises a pump housing 2 of substantially cylindrical shape, at least in an intermediate portion. The pump housing 2 comprises a blood flow inlet 21 and a blood flow outlet 22. In 1 it appears that the pump housing 2 consists of two separate sections, but these sections are either integral or joined into a single piece.

As in the enlarged view of the in 2 pump section shown along with those shown in FIGS 4 and 5 Illustrated front perspective views is better seen, the blood flow inlet 21 includes a primary blood flow inlet 211 and a secondary blood flow inlet 212. The primary blood flow inlet 211 surrounds the secondary blood flow inlet 212. The primary blood flow inlet 211 and the secondary blood flow inlet 212 are separated by an inflow separator 26. Within the inflow separator 26, the inflow separator 26 comprises an impeller bearing ring 27 which is 8th is shown separately. Furthermore, the pump device 11 includes a primary impeller 31, in which a secondary impeller 32 is integrated. The primary and secondary impellers 31, 32 can be rotated together about an axis of rotation 10. The secondary impeller 32 can, as in 7 shown the form of an inlay and be located within a secondary impeller cavity 312 of the primary impeller 31 . The secondary impeller cavity 312 is open to a pump section end PSE of the pumping device 11 . Alternatively, the primary and secondary impellers 31, 32 are formed integrally.

A primary blood flow 1BF flows from the primary blood flow inlet 211 to the primary impeller 31 outside the inflow separator 26 to be conveyed from the primary impeller 31 to the primary blood flow outlet 22 through a primary blood flow passage 30 . A secondary blood flow 2BF flows from the secondary blood flow inlet 212 through the inflow separator 26 to the secondary impeller 32 to be conveyed from the secondary impeller 32 to the primary blood flow passage 30 through a plurality of secondary blood flow passages 321 .

A blood flow that reaches the pumping device 11 at the end of the pump section can thus flow into the primary and secondary blood flow inlets 211, 212, preferably over almost the entire cross section of the pumping device 11, without significant deflection. Due to the central location of the secondary blood flow inlet 212, blood can also enter the pumping device 11 from the middle of the blood flow without being deflected. This is advantageous because blood flow is normally laminar flow, with flow velocity being greatest in the center.

The primary impeller 31 includes primary impeller blades 313 which extend into the primary blood flow passage 30 and between which primary impeller channels 311 are located. The primary impeller channels 311 have a primary slope at a primary channel inlet 314 at each end of the primary impeller channels 311 toward the pump section end PSE. The secondary impeller 32 comprises at least one and in particular exactly two secondary blood flow passages 321 in channel form, which are therefore also referred to as secondary impeller channels 321 below (see also 7 ). The secondary impeller channels 321 have a secondary slope at a secondary channel inlet 324 located at an upstream end of the secondary impeller channel 321 . The secondary slope is preferably the same as the primary slope or may vary to some degree so long as undesired flow conditions, such as e.g. B. turbulence can be avoided. At an end of the secondary impeller 32 toward a drive section end DSE, a communication hole 315 between the secondary impeller cavity 312 and one of the primary blood flow passages 311 is arranged. One end of this opening 315 in the direction of blood flow defines the secondary blood flow outlet 213. The secondary blood flow outlet 213 is arranged further radially outward with respect to the axis of rotation 10. FIG. Therefore, the blood is pushed outward in the radial direction by the centrifugal forces caused by the rotation of the secondary impeller 32 . In this way, the secondary blood flow 2BF is conveyed through the secondary blood flow inlet 212 and further through the secondary impeller channel 321 of the secondary impeller 32 and merges with the primary blood flow 1BF flowing through the primary impeller channel 311 of the primary impeller 31 . In this way, a pumped blood flow PBF is formed. The pumped blood flow PBF leaves the pumping device 11 at the blood flow outlet 22.

The primary and secondary impellers 31, 32 are mounted together in an impeller bearing 37. They are connected via the secondary impeller cavity 312 or integrally molded as a single piece. The inflow separator 26 includes an impeller bearing ring 27 disposed within the inflow separator 26 . An outer wheel bearing surface 277 of the wheel bearing 37 is arranged on the inside of the wheel bearing ring 27 . The impeller bearing 37 further includes an inner impeller bearing surface 327 disposed on an outer periphery of the secondary impeller 32 .

The primary impeller 31 is rigidly connected to a tapered portion 314 leading to the blood flow outlet 22 . The tapered portion 314 directs the pumped blood flow PBF radially outward with respect to the axis of rotation 10 . The blood then reaches the blood flow outlet 22.

A drive section 4 , which includes a stator 40 and a rotor 41 , is arranged inside the pump housing 2 of the pump device 11 from the tapered section 314 in the direction of the pump section end PSE. An axial gap 401 is arranged between the stator 40 and the rotor 41 . In order to cool the stator 40 and the rotor 41, the axial gap 401 is flushed with blood. For this purpose, an auxiliary blood flow ABF enters the drive section 4 through an auxiliary blood flow inlet 23 arranged at the end of the drive section DSE. The blood is then conveyed by an auxiliary impeller 42 through an auxiliary pump gap 423 which is arranged between the auxiliary impeller 42 and an inner wall of the pump housing 2 . From there the blood continues to flow into the axial gap 401 . The auxiliary blood flow ABF enters a radial gap 241 from the axial gap 401 . At the radially outer end of the radial gap 241, an auxiliary blood flow outlet 24 is arranged. The auxiliary blood flow ABF flows in the axial gap 401 in a direction opposite to the pumping direction of the primary and secondary impellers 31, 32. The auxiliary blood flow ABF within the drive section 4 also essentially flows in a direction opposite to a general blood flow GBF flowing around the blood pump 1.

As in the enlarged view in 3 better seen, a rotor bearing ring 43 surrounds the auxiliary impeller 42. The auxiliary impeller 42 includes auxiliary impeller blades 421. A radial rotor bearing 47 is arranged at the drive section end DSE, which has an outer rotor bearing surface 4211 and an inner rotor bearing surface 4311, between which an axially running bearing gap is arranged. The outer rotor bearing surface 4311 is arranged on the rotor bearing ring 43 . The blood conveyed by the auxiliary impeller 42 flows through the bearing gap and on to the axial gap 401 between the rotor 41 and the stator 40. From the axial gap 401 the blood flows to a radial gap 241. The radial gap 241 extends between the tapered section 314 of the primary impeller 31 and the stator 40. At the transition between the radial gap 241 and the surroundings of the pumping device 11, an auxiliary blood flow outlet 24 is arranged. The auxiliary blood flow outlet 24 is arranged perpendicularly to the axis of rotation 10 . Here the blood from the auxiliary blood flow ABF joins the pumped blood flow PBF from the pump section 2 and the surrounding general blood flow GBF. When the auxiliary blood flow outlet 24 is positioned close to the outer diameter of the pump housing 2 and close to the primary blood flow outlet 22, as shown, the pumped blood flow PBF and the general blood flow GBF, due to their flow velocity, assist in drawing blood from the radial gap 241. This causes the auxiliary blood flow ABF reinforced by the axial gap 401.

In the center of the auxiliary impeller 42 through which the axis of rotation 10 extends and on a side of the auxiliary impeller 42 opposite to the rotor 41, a hump 422 is arranged. A bearing pin 44 is arranged in the direction of the axis of rotation 10 towards the end of the drive section DSE and adjacent to the hump 422 . The bearing bolt 44 is connected to the pump housing 2 . An axial bearing surface of the bearing pin 44 toward the auxiliary impeller 42 has a convex shape. The axis of rotation 10 passes through an apex of the axial bearing surface of the bearing pin 44 and through an apex of the axial bearing surface of the boss 422. In this way, the bearing pin 44 cooperates with the boss 422 and forms an axial bearing to absorb axial forces with respect to the axis of rotation between the To transfer hump 422 and the bearing pin 44, wherein the aforementioned parts are rotatable relative to each other. Obviously, the contact area is small, so the torsional friction is low.

The drive section end of the blood pump 1 includes one or more, preferably three, auxiliary inlet ports 231. The auxiliary inlet ports 231 extend from the auxiliary blood flow inlet 23 to an auxiliary impeller cavity 232 in which the auxiliary impeller 42 is located. Thus, the blood flows from the auxiliary blood flow inlet 23 to the auxiliary impeller 42 via the auxiliary inlet through-holes 231.

At least one wire through hole 25 is arranged at the driving section end DSE of the pumping device 11 . The wire through-holes 25 can extend from the catheter 5 to the stator 40 . Preferably, three wire through holes 25 are arranged around the axis of rotation 10 . A wire through hole 25 may be disposed between two auxiliary inlet through holes 231 . At least one supply line 51 , 52 and/or 53 which is connected to the stator 40 can extend in a wire through-hole 25 . Preferably, umbilicals 51, 52 and/or 53, as shown, extend through the interior of catheter 5 to the exterior of the patient's body. The supply lines 51, 52 and/or 53 run from the catheter 5 to the stator 40 without contact with the blood.

4 14 is a front perspective view of the pump section end PSE of pump section 3. As shown, secondary impeller 32 is located within impeller bearing ring 27. FIG. The impeller bearing ring 27 is arranged inside the inflow separator 26 . As an alternative to this embodiment, the additional impeller bearing ring 27 can be omitted so that the outer impeller bearing surface 277 is formed by the inflow separator 26 . The inflow separator 26 is fixed here by three struts 28 between the primary blood flow 1BF and the secondary blood flow 2BF. The secondary blood flow 2BF is shown flowing into the secondary impeller 32 through the secondary blood flow inlet 212 located at an inflow into the impeller bearing ring 27 . In the secondary impeller 32, the blood flows along the secondary impeller channel 321 and through the through opening 315 to the secondary blood flow outlet 213. Here the secondary blood flow 2BF combines with the primary blood flow 1BF to form the pumped blood flow PBF.

5 shows the pump section end PSE of the pump section 3 in a perspective view, with the pump housing 2 being shown transparently. The through hole 315 and the secondary blood flow outlet 213 are arranged between two primary impeller blades 313 . As shown, the struts 28 are connected by an outer strut connecting ring 29 . The strut connection ring 29 is arranged inside an inner peripheral surface of the pump housing 2 at the pump section end PSE. The impeller bearing ring 27 is supported by the struts 28 . It is conceivable that the strut connection ring 29 and the Strive to manufacture 28 in one piece. Preferably, the impeller bearing ring 27 is also part of this piece. This piece can also be designed in one piece with the pump housing 2 .

6 shows a perspective view of the pump section end PSE of the pump section 3, in which the pump housing 2 differs from that in FIGS 3 until 5 shown embodiment is transparent, wherein the inflow separator 26 at a downstream end of the inflow separator 26 has at least one, preferably three, recesses 261. The recess 261 is arranged between two struts 28 . The impeller bearing ring 27 is part of or integral with the inflow separator 26, and the recess 261 also extends through the impeller bearing ring 27. Due to the recess 261, the secondary impeller channel 321 has an increased cross-section as it aligns with the recess 261 during rotation of the secondary impeller . The secondary impeller 32 extends within the impeller bearing ring 27 in the direction of the pump section end PSE at most to one end of the recess 261. This has the effect that during operation an edge of the recess 261 runs over the inner impeller bearing surface 327 and removes or drains blood clots as they begin to form. preferably prevented since the counterpart of the rotating thrust bearing surface 328 at the recess 261 is in direct blood contact. This helps avoid stagnant blood inside the thrust bearing. The inner impeller bearing surface 327 also has edges 325, as in 7 can be seen causing blood clots to be removed from the outer impeller bearing surface 277 ( 8th and 9 ).

7 shows the secondary impeller 32 in detail in a perspective view. The secondary impeller 32 is designed there as an inlay and has approximately the shape of a cylinder. It can consist of a different material than the primary impeller 31, for example a ceramic material. The inlay consists of a cylindrical section 323 which is arranged within the secondary impeller cavity 312 of the primary impeller 21 . A peripheral projection 329 provides an axial stop for the secondary impeller 32 within the secondary impeller cavity 312 . Two secondary impeller channels 321 are arranged on the end of the secondary impeller 32 facing the pump section. The secondary impeller channels 321 have their largest cross-section at the upstream end of the secondary impeller 32. Thus, the cross-section of the channels 321 decreases away from the blood flow inlet 21. In this manner, blood is directed from a primarily axial direction to an axial-radial direction as it flows through secondary impeller passage 321 .

The secondary impeller channels 321 are arranged asymmetrically with respect to the axis of rotation 10 of the secondary impeller 32 . At an end of the secondary impeller 32 facing the blood flow inlet 21, the axis of rotation 10 extends through one of the secondary impeller channels 321. In this way, the center of rotation, which lies on the axis of rotation 10, does not coincide with a solid part of the secondary impeller 32. This has the advantage that blood coagulation in the center of rotation, where there is no speed difference to the adjacent blood flow, can be avoided.

Edges 325 are arranged at the transition between the secondary impeller channels 321 and the inner impeller bearing surface 327 . As previously mentioned, these ridges 325 serve to push away clot formation on the outer impeller bearing surface 277 . The inner impeller bearing surface 327 forms an inner surface of a journal bearing at the pump section end PSE. The secondary impeller 32 further includes an axial impeller bearing surface 328 . The impeller axial bearing surface 328 forms part of the thrust stop or thrust bearing mentioned above. The thrust stop may be in the form of a thrust bearing capable of transmitting forces from the secondary impeller 32 to the bearing ring 27 during rotation of the impeller. The thrust bearing is required to counteract the axial force resulting from the scavenging action of the impeller.

8th shows an enlarged view of the impeller bearing ring 27. The outer impeller bearing surface 277 is arranged on the inside of the impeller bearing ring 27. FIG. The impeller bearing ring 27 includes a thrust bearing ring surface 278 . As illustrated, the thrust bearing ring surface 278 may be disposed at an axial end of the impeller bearing ring 27 .

9 shows a perspective view of an impeller bearing ring 27 according to a further embodiment, which differs from that in FIG 8th shown embodiment differs in that it has the already mentioned recesses 261, which are arranged at a downstream end of the impeller bearing ring 27. The number of recesses 261 preferably corresponds to the number of struts 28.

10 shows a perspective view of a cross section through the drive section end DSE of the drive section 4. Rotating parts are not shown in section. As shown, the auxiliary blood flow ABF enters the pump housing 2 at the auxiliary blood flow inlet 23 . The auxiliary run Wheel 42 accelerates the blood, which continues to flow into axial gap 401. As indicated by the arrow ABF in the axial gap 401, the blood does not flow directly in the direction of the axis of rotation 10, but has a strong flow component in the circumferential direction, so that it flows along the axial gap 401 in a helical manner.

11 shows a perspective view of one end of the rotor 41 at the drive section end DSE of the pumping device 11. The auxiliary blades 421 of the auxiliary impeller 42, which extend straight in the radial direction, can be clearly seen. The auxiliary impeller blades 421 form the inner rotor bearing surface 4211 of the radial rotor bearing 47 on their outer circumference. Furthermore, the auxiliary impeller blades 421 each have a bevel 4212 . This bevel 4212 is advantageous in order to form a tapered drive section end DSE of the pumping device 11, as in FIG 10 shown. Furthermore, the auxiliary impeller blades 421 have radially extending end surfaces 4214 at an axial end of the secondary impeller 42 . A hump 422 is formed in the center of the axial end of the secondary impeller 42 . The hump 422 interacts with the bearing pin 44, as in FIG 10 shown.

11A FIG. 12 further shows the rotor bearing ring 43 which is arranged around the inner rotor bearing surface 4211 of the auxiliary impeller 42. FIG. The outer rotor bearing surface 4311 of the rotor bearing ring 43 together with the inner rotor bearing surface 4211 of the auxiliary impeller 42 forms the rotor bearing 47. The auxiliary impeller 42 has an axial length L and a diameter D. Alternatively, the rotor bearing ring 43, as in 11B 1, may have recesses having a shape, function, and configuration similar to recesses 261 of impeller bearing ring 27 described above.

12 12 shows an end of the rotor 41 which is connected to the tapered section 314 of the primary impeller 31 in a perspective view. A tertiary impeller 242 is disposed between the tapered portion 314 and the pump portion end of the rotor 41 and extends radially from an outer diameter of the rotor 41 to an outer diameter of the tapered portion 314 to form a shoulder. An axial plane of this shoulder forms a rotatable wall 2411 of the radial gap 24. From the rotatable wall 2411, the tertiary impeller blades 2412 protrude towards the drive section end DSE of the pumping device 11. Preferably, the tertiary impeller blades 2412 extend axially along the axis of rotation 10. In particular, the tertiary impeller blades are 2412 straight and extend in the radial direction relative to the axis of rotation 10. Alternatively, the tertiary impeller blades 2412 can also be omitted (not shown).

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2017021465 [0007]

Claims (34)

Intravascular blood pump 1, comprising a pump device 11 with a pump section 3 and a drive section 4, wherein - the pump section 3 comprises a pump housing 2 having a primary blood flow inlet 211 and a primary blood flow outlet 22 hydraulically connected by a primary passage 30, and the drive section 4 comprises a stator 40 and a rotor 41 rotatable about an axis of rotation 10 and so configured is that it rotates a primary impeller 31, the primary impeller 31 being configured to promote a primary blood flow from the primary blood flow inlet 211 to the primary blood flow outlet 22 along the primary passage 30, - the drive section 4 further comprises an auxiliary blood flow inlet 23 and an auxiliary blood flow outlet 24 hydraulically connected by an auxiliary passage extending through an axial gap 401 between the rotor 41 and the stator 40, and an auxiliary impeller 42 mounted at a drive section end DSE of the Rotor 41 and rotatable about the axis of rotation 10 together with the rotor 41, wherein the auxiliary impeller 42 comprises one or more auxiliary impeller blades 421 configured to provide auxiliary blood flow from the auxiliary blood flow inlet 23 to the auxiliary blood flow outlet 24 along an auxiliary passage in one direction convey to a pump section end PSE of the pumping device 11, - the rotor 41 is mounted in a blood flushed radial sliding rotor bearing 47 having an inner rotor bearing surface 4211 and an outer rotor bearing surface 4311, and - The auxiliary impeller 42 forms the inner rotor bearing surface 4211 of the radial sliding rotor bearing 47. Intravascular blood pump after claim 1 , wherein the inner rotor bearing surface 4211 and the rotor 41 have a common outer diameter. Intravascular blood pump according to any of the Claims 1 and 2 , wherein the auxiliary impeller 42 is a radial or radial-axial conveying impeller. Intravascular blood pump according to any of the Claims 1 until 3 , wherein the auxiliary impeller blades 421 each have an outer peripheral surface and wherein the inner rotor bearing surface 4211 is formed by the outer peripheral surfaces of at least two of the auxiliary impeller blades. Intravascular blood pump according to any one of the preceding claims, wherein at least one of the auxiliary impeller blades 421 protrudes axially from the auxiliary impeller 42. The intravascular blood pump of any preceding claim, wherein at least one of the auxiliary impeller blades 421 extends radially from the blood flow inlet at least to the axial gap 401. Intravascular blood pump according to one of the preceding claims, wherein at least one of the auxiliary impeller blades 421 extends in a radial direction relative to the axis of rotation 10 . Intravascular blood pump according to one of the preceding claims, wherein at least one of the auxiliary impeller blades 421 forms an auxiliary pump gap 423 with an inner wall of the pump housing 2 . The intravascular blood pump of any preceding claim, wherein the outer peripheral surface of at least two of the auxiliary impeller blades 421 is circumferentially inclined to form a sliding rotor hydrodynamic bearing 47. The intravascular blood pump of any preceding claim, wherein the inner rotor bearing surface 4211 has a radially protruding ridge whose apex extends circumferentially. An intravascular blood pump according to any one of the preceding claims, wherein the inner rotor bearing surface 4211 is made of ceramic material. Intravascular blood pump after claim 11 , wherein the auxiliary impeller 42 is an integral piece of ceramic material. An intravascular blood pump as claimed in any one of the preceding claims, wherein part of the pumping device 11 which forms the outer rotor bearing surface 4311 of the radially sliding rotor 47 is a rotor bearing ring 43. Intravascular blood pump after Claim 13 , wherein the outer rotor bearing surface 4311 is made of ceramic material. Intravascular blood pump after Claim 14 , wherein a part of the pumping device 11 forms the outer rotor bearing surface. Intravascular blood pump according to one of the preceding claims, comprising an axial rotor bearing or an axial-radial rotor bearing with an axial or an axial-radial rotor bearing surface, respectively, which is arranged on the auxiliary impeller 42. Intravascular blood pump after Claim 16 , wherein at least the axial or axial-radial rotor bearing surface of the auxiliary impeller 42 consists of ceramic material. Intravascular blood pump according to any of the Claims 11 , 12 , 14 , 15 and 17 , wherein the ceramic material is silicon carbide. Intravascular blood pump according to one of the preceding claims, wherein an axial length of the auxiliary impeller 42 is smaller than a maximum outer diameter of the auxiliary impeller 42. An intravascular blood pump according to any one of the preceding claims, wherein the primary impeller 31 and the auxiliary impeller 42 are arranged on opposite sides of the rotor 41. An intravascular blood pump according to any one of the preceding claims, wherein a radially outer edge of one or more of the auxiliary impeller blades 421 is chamfered. The intravascular blood pump of any preceding claim, wherein the auxiliary blood flow outlet 24 is located outside of the primary passage 30. The intravascular blood pump according to any one of the preceding claims, wherein the auxiliary blood flow inlet 23 comprises a plurality of auxiliary inlet through-holes 231 arranged around the axis of rotation 10. Intravascular blood pump after Claim 23 , wherein in a space between two of the auxiliary inlet through holes 231, a wire duct 25 for an electric supply wire 51, 52, 53 for the driving section 4 is arranged. Intravascular blood pump after Claim 23 or 24 , wherein the axial gap 401 has an inlet arranged to allow blood to flow into the axial gap 401, and wherein an internal end 233 of the auxiliary inlet through hole 231 is arranged further radially inward than a radially innermost portion of the inlet into the axial Gap 401. An intravascular blood pump according to any one of the preceding claims, wherein the pumping device 11 comprises a tertiary impeller 242 arranged to draw the auxiliary blood flow through the auxiliary passage. Intravascular blood pump after Claim 26 , wherein the tertiary impeller 242 is rotatable about the axis of rotation 10 together with the rotor 41. Intravascular blood pump according to any one of the preceding claims, wherein the auxiliary blood flow outlet 24 is arranged in a radial gap 241 between the primary impeller 31 and the stator 40. Intravascular blood pump after claim 28 , wherein the auxiliary blood flow outlet 24 is arranged such that, in use, a pumped blood flow PBF exiting the primary blood flow outlet 22 flows past the auxiliary blood flow outlet 24. Intravascular blood pump after claim 28 or 29 , wherein a rotatable wall 2411 of the radial gap 241 is rotatable together with the rotor 41. Intravascular blood pump after Claim 30 , wherein a stationary wall 2410 of the radial gap 241 opposite the rotatable wall 2411 of the radial gap 241 is mechanically connected to the stator 40. Intravascular blood pump according to any of the claims 28 until 31 , including Claim 27 , wherein the tertiary impeller 242 is arranged in the radial gap 241. Intravascular blood pump after Claim 32 , including Claim 30 , wherein the tertiary impeller 242 includes at least one tertiary impeller blade 2412 protruding from the rotatable wall 2411 of the radial gap 241 . Intravascular blood pump according to any of the Claims 32 and 33 , wherein an inlet to the tertiary impeller 242 is located at an outlet end of the axial gap 401 .

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